Optic neuritis is usually caused by demyelinating diseases of the central nervous system, and generally requires the following examinations to be completed. First, it is necessary to complete an MRI scan of the optic nerve to assess if there is any abnormal swelling or abnormal signals in the optic nerve. Second, these patients also need to undergo brain MRI and spinal cord MRI scans, as optic neuritis patients may experience demyelination of brain white matter and the spinal cord. Third, it is important to complete examinations of serum and cerebrospinal fluid for aquaporin-4 antibodies. If this antibody is positive, it is of significant reference value for the diagnosis of neuromyelitis optica. Additionally, visual evoked potentials and examinations like OCT of the fundus are also necessary.